Computer Logic

Computer Logic

* Bistable Devices

           - Also known as a 2-STATE DEVICE
           - Like a switch on a wall because only one of two possible states at any given time either on or off     
           - One example is a bulb it may be lluminted or not illuminated.

 * What are computers made of?

     - Transistors are elementary building block for all modern computer and are much like the light switch and it is also a solid-state device.
     -  This allows it to be fast as well as extremely small.

* Binary
   - Binary is a number system.
     - It is represented by 0's and 1's.

* Using many bits
     - A bit is a single digit from a binary number. It is either a 1 or a 0.
     - To find how many different values we can represent by the number of bits, we need to remember the equation 2 to the power of the number of bits.

*  Number Convertions
       - The bit with the smallest value is called the LEAST SINGNIFICANT BIT (LSB)
       - The bit with the largest value is called the MOST SIGNIFICANT BIT (MSB)

* ASCII
    - This stands for AMERICAN STANDARD CODE for INFORMATION INTERCHANGE
    -  This is an 8-bit code used to represent characters in binary.
    - This code can store 256 characters.

* Units of storage
   - 8 bits represent 1 byte.

* Unicode
     - Unfortunately the ASCII code was not enough and so we invented the unicode.
     - This allows 16 bit instead of 8 bit.
     - Instead of 265 it represents 16,536.
     - An organisation known as the Unicode Consortium was formed to deal with these and other problems.

    * Analogue and Digital Data
       - An analogue device is one in which data is represented by some quantity which is continuously changing. Like the traditional wall watch.
          - A digital device is a device that shows data at discrete intervals. Like the Digital thermometer.

* Converting Analogue to digital
    - Modem is also known as MODulator DEModulator.
      - Its purpose is to convert between the analogue signals used in telephone cables and the digital signals used by a computer.

* Sound card
   - It is needed to output for music or speech from programs, CD-ROMs, and input analogue sound signals from a microphone.

* Network card
     - It lets computers communicate with other computers that are networked together.
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